I read OpenQuest1 cover to cover, here's what I thought...
1. Very clean and straightforward layout. This book is easy to navigate and rules were in the first or second place I'd look for them.
2. The ruleset is a bit light for me in places, mainly modifier variety and and a lack of some rules like location HP and armor/weapon breakage. However, this is part of the author's aim, and it seems like it would be trivial to modify with other d100 rules.
3.The art is well composed, though a bit cartoony for my taste. I felt the same way about some MRQ books - if I were makng RPGs they'd be illustrated like Osprey military manuals and Renaissance paintings. The Grog is strong in this one, and I know my taste for romantic realism isn't universal.
4. This pdf was free and apparently under some kind of OGL. Between that and the MRQ SRD I feel like I might want to build my own variant to address the differences in style I have with the author, this makes it quite useful.
5. Overall, a strong, easy-to-learn version of d100 that could be used to introduce newbs and as a complete game in its own right. This game is simpler than the B/X D&D I run, in fact it is just screaming to be stacked with Classic Fantasy to create a more D&D and less AD&D game.
Overall, Wakboth approves the use of this game, and if Kajabor doesn't turn my bank account into a gaping ruin I might pick up a print copy of OQ2.